Breast cancer is the most frequently diagnosed cancer and the second leading causes of cancer-related death among women in the United States [1]. According to the American Cancer Society (ACS) estimation in 2015, 231,840 new breast cancer cases were diagnosed, which accounts for 29% of all newly diagnosed female cancer patients. And 40,290 of breast cancer deaths cover 15% of cancer-related death among women [1]. Early diagnosis plays a key role in patients' prognosis. Mammography is currently the most widely used method in breast cancer scanning. However, the outcome is not satisfactory because of the high false positive rate [2].
The overdiagnosis of breast cancer in screening mammography is wide, from 0% to upwards of 30% [3]. Women with abnormal screening mammograms undergo additional expensive magnetic resonance imaging (MRI) and tissue sampling (by fine-needle aspiration, core biopsy, or excisional biopsy). Even worse, about 10% of women will be called back from each screening examination for further testing, but only 5% of these women will have cancer, and the others turn out to be benign [4]. Chiarelli et al [5] had reported that breast MRI plus mammography is an effective way for breast cancer screening. However, it is very expensive and it has not been demonstrated that screening high-risk populations with MRI has translated into a survival benefit [6]. Further, MRI has a high false-positive rate and could lead to high frequency of futile biopsies with additional stress and cost [7]. To avoid unnecessary expensive and invasive screening for those benign patients, a better method is urgently needed. Blood-based tumor marker is one of the research hotspots in diagnosis of cancers. However, they are not used in clinical trials up to-date [8-10]. Serum tumor markers such as CA15.3 and BR27.29 have low sensitivity and thus are not used for breast cancer detection [11]. Thus, there is a pressing need for minimally invasive methods and early diagnosis of malignant breast lesions.
Lipids are involved in regulating many physiological activities, such as energy storage, structure, apoptosis, and signaling [12]. Many studies have reported that, as a major component of metabolic syndrome, dyslipidemia plays an important role in the carcinogenesis of various cancers, including in prostate cancer, ovarian cancer and kidney cancer [13-15]. For breast cancer, it has been well shown that metabolomics or lipidomics had potential for cancer diagnosis and progression [16-18]. However, most of these studies have been just focused on total levels of lipids in cancer patients, and only a few of them included patients with benign breast diseases. Recently, Yang et al. performed a comprehensive evaluation of plasma lipid profiles with benign breast disease patients in only 5 breast cancer cases and 6 benign patients, indicating the diagnostic efficiency of the lipid markers in these diseases [19].
This study uses lipidomics technology and electrospray ionization tandem mass spectrometry (ESI-MS/MS) to make quantitative analysis for plasma samples in both a training set and a validation set including a total of 84 breast cancer patients and 110 benign patients. The whole set (the combined training and validation sets) was used to verify the credibility of the results. In this study a panel of plasma lipid species were identified which were able to distinguish early stage of cancer from benign lesions, and serve as potential biomarkers for early diagnosis of breast cancer.
What is needed is a biomarker panel for diagnosing breast cancer.